The present invention relates to a card connector. Conventionally, electronic devices such as personal computers, portable phones, PDAs (Personal Digital Assistants), digital cameras, video cameras, music players, game machines, and vehicular navigation systems are quipped with connectors for cards so that various memory cards such as SIM (Subscriber Identity Module) cards, MMC® (Multi Media Cards), SD® (Secure Digital) cards, mini SD® cards, Memory Stick®, and Smart Media® can be used.
In this case, it might be considered to use a delay switch for detecting an early stage of motion to withdraw a card mounted in the above-described electronic device from the device. For example, if a memory card is withdrawn from an electronic device while a computing means of the electronic device is accessing to the memory card to execute a process, a data bus which connects the computing means and the memory card is disconnected in the middle of the data transmission process. Therefore, the data might be damaged, or the computing means may stop operating and never recover. The above-mentioned delay switch detects the initial action of withdrawing the memory card, and this provides time to safely disconnect the computing means and the memory card before the terminals of the card connector and the contact pads of the memory card are disconnected from each other.
However, in some so-called “push-in/push-out” or “push-push” type of card connectors which are used with a relatively small card, the moving distance of a memory card is short because of the small size, and therefore it is difficult to secure a sufficient length of delay time that starts from a pushing action to eject a memory card and ends when the terminals of the card connector and the contact pads of the memory card are disconnected from each other.
A certain technology capable of prolonging a travel time of a memory card has already been proposed for a push-push type card connector. (For example, refer to Japanese Patent Application Laid-Open (Kokai) No. 2005-302423.)
FIG. 16 is a view showing a heart cam mechanism in a conventional card connector.
In this drawing, reference numeral 314 represents a heart shaped cam member, which is slidably attached to a housing of a card connector (not shown) while being urged in one direction by a coil spring 315. One end of a pin member 317 is pivotally connected to a supporting portion 304 of the housing, and the free end 305 of the pin member 317 is engaged in a cam groove 318 formed in the top surface of the heart cam member 314. In addition, the cam groove 318 includes a first guide portion 307 and a second guide portion 308, both being formed into a zigzag shape.
When a memory card is inserted into the housing, the heart cam member 314 is pushed toward the back of the housing by the memory card that is pushed by a finger of a user, and moves in the direction indicated by the arrow A. At this time, the free end 305 of the pin member 317 passes through the zigzag-shaped first guide portion 307. Therefore, even if the user remove his/her finger from the memory card by mistake, the first guide portion 307 puts a brake on the pin member 317 so that the heart cam member 314 does not move back rapidly.
Moreover, when the user pushes a memory card by his/her finger to remove the memory card from the housing, the free end 305 of the pin member 317 engaged and stopped in the cam groove 318 is unlocked. As a result, the heart cam member 314 is released, and moves with the memory card in the direction indicated by the arrow B. At this time, the free end 305 of the pin member 317 moves past the zigzag-shaped second guide portion 308. Therefore, braking is applied to the pin member 317, and the heart cam member 314 slows down. This prevents the memory card from popping out from the housing of the card connector.
Nevertheless, the conventional card connector failed to take into consideration the use of a delay switch and thus, could not secure a sufficient length of time for removing a memory card from the housing. In a heart cam mechanism as described above, the heart cam member 314 slows down by allowing the free end 305 of the pin member 317 to pass along the zigzag-shaped second guide portion 308. However, if the zigzag angles are too acute, the free end 305 is not permitted to pass through the second guide portion 308, and eventually stops moving. Hence, in practical use, the zigzag angles must be increased so that the free end 305 can move along the second guide portion 308 smoothly, thus decreasing the ability to significantly slow down the heart cam member 314 to secure a sufficient length of time for withdrawing a memory card from the housing.